export class OnboardingUtils {
    private static readonly USER_GUIDE_TAG_ID = "userGuideSnippet";
    private static instance: OnboardingUtils;

    private constructor(){}

    public static getInstance(): OnboardingUtils {
        if(this.instance == null){
            this.instance = new OnboardingUtils();
        }
        return this.instance;
    }

    public init(apiKey: string, ctx: EnvironmentContext): Promise<void> {
        if(!apiKey){
            return Promise.resolve();
        }
        this.injectScript(apiKey);
        this.register(ctx);
        return Promise.resolve();
    }

    private injectScript(apiKey: string){
        if(window.document.head.querySelector(`script#${OnboardingUtils.USER_GUIDE_TAG_ID}`)){
            return;
        }

        const scriptEl = document.createElement('script');
        scriptEl.setAttribute("id", OnboardingUtils.USER_GUIDE_TAG_ID);
        scriptEl.innerText = `(function(g,u,i,d,e,s){g[e]=g[e]||[];var f=u.getElementsByTagName(i)[0];var k=u.createElement(i);k.async=true;k.src='https://static.userguiding.com/media/user-guiding-'+s+'-embedded.js';f.parentNode.insertBefore(k,f);if(g[d])return;var ug=g[d]={q:[]};ug.c=function(n){return function(){ug.q.push([n,arguments])};};var m=['previewGuide','finishPreview','track','identify','hideChecklist','launchChecklist'];for(var j=0;j<m.length;j+=1){ug[m[j]]=ug.c(m[j]);}})(window,document,'script','userGuiding','userGuidingLayer','${apiKey}');`;
        window.document.head.appendChild(scriptEl);
    }

    private register(ctx: EnvironmentContext){
        (window as any).userGuiding.identify(`${encodeURIComponent(ctx.userID)}-${encodeURIComponent(ctx.userName)}-${encodeURIComponent(ctx.clientGaId)}`, ctx);
    }
}

export class EnvironmentContext {
     userID: string = "";
     userName: string = "";
     partnerName: string = "";
     sysVersion: string = "";
     environment: string = "";
     clientGaId: string = "";
}